Spark-plug



u. L. CUEVAS/ SPARK PLUG. v APPLICATION FILED FEB. 6 I919.

.- Swueutoz Fisz'n .Z. Jueras Patented Mar. 16, 1920.

unrrnn STATES P E QFFICE I URSIN L. CUEVAS, OF CUEVAS, KISSISSIPPI.

SPARK-PLUG.

. Specification of Letters Patent.

' PatentedMar. 16', 1920.

.Application filed Februaryfi, 1919. Serial No. 275,279.

To all whom it may concern:

Be it known that I. URSIX L. CUEVAS, a

v citizen of the United. States, residing at Cuevas, in the county of Harrison and State of Mississippi, have invented new and use- 'ful Improvements in'Spark-Plugs, of which the following is a specification."

My present invention pertains to spark plugs, .and particularly to the electrode. and

insulating structure as embodied insuch p s.

An objectof the inventionis to provide a spark plug in which the spark ap is between two spaced rings, with ,which structure-firing can take place at any point between-the two rings, thus reducing the liability of fouling and allowing tor rotation of the spark gap around the ringslif' Pen.

. chance any part should become foul.

A further objectresides in so construct-- ing the central electrode and the insulator core ,that an absolutely tight joint is accom-. plished and leakage or loss of compression .15 absolutely precluded. 4 .Yet another object is to arrange, in conjunction "with the insulator core and central electrode, a shell which offers maximum protection to the core and at the same time presents a chamber adjacent the electrodes, thus insuring firing of the gas charge.

- With these and other objects in view which will be apparentfrom the drawings in conjunction 'with. the specification and ,cIaims, this. invention includes certain novel features of construction and combinations of parts which will now beset forth-Y In the drawings:

Figure 1 is a view in elevation of a spark plug constructedafter the manner of my invention.

Fig. 2 is a-view n vertical section through the plug.

Fig. 3 is a view elevation of the sparking end ofthe plug.

Fig. 4 is a perspective viewof the central conductor or electrode.

Fig. 515 an enlarged fragmentary detail H view showinga modification of the electrode structure.

The shell 1 is threaded'at one end as at 2, for securement within the usual spark plug opening, and tronrt-lns threaded end 'the central bore is gradually tapered down to about midway'of the body portion. where the bore is enlarged to provide a shoulder 3. The remaining end of the shell is madeof around the stem above cap 16.

polygonal form to take awrench, and the 7 central bore is enlargedand is internally screwthreaded at l, a shouldel," being tormed at 5 at the inner end of the ;screwthreaded portion.

. The insulator core 6 has an axially extending opening 7 thereiin and this core which is preferably made of j-nica is shaped to fit within the bore of shell 1. and an enlarged portion 8 being provided thereon to seat upon shoulder 3, and that portion of end and the enlargement is of such lengtlu 'tliatwlienthe ste n l'Ois fitted into opening T. of thecore. shoulder 11 will bear against shoulder 9. At its extreme inner end said stem is widened out into a conical shape conforming substantially to the inner flared end of opening 7, and spokes 12 are formed on the-inner extremity of the stem to extend radially therefrom. an electrode ring 13 being.carried by said spokes concentrically around the stem.

\Yhen the plug is to be assembled a layer of asbestos paper or other fireproof packing l-l is placed around the conical end 15 of stem 10. so that as the stem is inserted into opening 7 a'packi'ng is provided between the conical end and; the flared portion of the opening. A cap 16 is then placed over the threaded end of stem 10 and is brought down over the outer end of core 6, washer 1'7 and lock washer 18 then being placed;

A clamp nut 19 is nextturned onto the threaded end of stem 10, and when turned down. will bring the conical portion 15 of said stem to a packing seat against the sheet material at- 11. excessive inward movement of the stem sufficient to split the inner endlof core 6 being stopped by engagementof shoulder 11 with shoulder 9. Thumb nut '20, of large proportion. is turned onto the threaded end of stem 10 to be used in securing a circuit wire thereto.

From the enlarged portion 8, core 6 is rethat when the plug is assembled leakage beangular edges are presented on the inside 7 duced in size on a gradual taper toward captweem core and cell is positively precluded.

When the core, carrying the central electrode, is secured in place, electrodering 13. is positioned at the externally threaded end of shell 1, and as this ring-is of less diameter than. the bore of the shell a space is providedentirely around the ring. A

' ground electrode 24, in the form of a ring,

is carried at the extreme inner end of shell f 1', and this ring 24, which is preferably substantially circular is larger than ring 13 to thus preserve a spark gap between the cen-.

Vhile thetral electrode and the shell. 4 ring '13 and ring 24 may be substantially circular in cross section, these rings might be of the ,form illustrated in Fig. 5, where of-rin'g 2 P'and the outer side of ring 13*.

'In-use, the parts of my improved spark plug'are assembled as shown in Figs. 1 and 2, the .diameters of rings 13 and 24being calculated to give a proper spark gap between the two rings, and ring 13 being spaced evenly and'held concentrically within ring 24. The plug is then fitted for use in'the usual manner and as the circuit con= nection to the stem 10 and the grounded shell l-is' established and broken, the current will jump the gap between rings 13 and 24:. Where both rings are clean, several fat sparks may pass, and if either ring becomes" fouled the spark may be concentrated at one point, however, as the explosion charge is free to flow into the shell around the central 'ge'lectrode, soot and carbon will be'blown out 'witheach explosion. Although the plug self-cleaning in the respect as mentioned, if any part, of either electrode becomes fouled the spark will rotate around the rings and it will be seen that clogging of the plug to such an extent that the entire spark gap is closed will be practically impossible.

While, in the foregoing, I have described I specific embodiments, and have mentioned .an insulating core carried within said shell,

a central conductor member supportedby said core and provided with radially extending spokes at. its inner end, said shell having a ground electrode ring of substantially circular cross section 'formed around the inner end thereof in line with the spokes as 'the central conductor member is supported by the insulating-core, and an electrodering of substantially circular cross section and carried by said spokes concentrically within and spaced from said ground electrode ring.

2. A spark plug including with a shell, an insulator core mounted in saidshell, having an axial opening therethroug'h enlarged adjacent its inner end and flared at said end, a central conductor having a stem increased in diameter at its innerend and shaped to be of widened out conical form at this extremity, a packing around said conical portion to bear withm the flared end'of said opening, means to draw the conical portionof said stem against said packing, said central conductor having spokes radiating from the widened conical end thereof, an electrode ring carried by said spokes concentrically around said conductor, and a ground electrode of ring form carried by said shell concentrically around and spaced from said electrode ring. a

In testimony whereof, I affix my signature.

URSIN L; GUEVAS. 

